////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2009, Daniel Kollmann
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, are permitted
// provided that the following conditions are met:
//
// - Redistributions of source code must retain the above copyright notice, this list of conditions
//   and the following disclaimer.
//
// - Redistributions in binary form must reproduce the above copyright notice, this list of
//   conditions and the following disclaimer in the documentation and/or other materials provided
//   with the distribution.
//
// - Neither the name of Daniel Kollmann nor the names of its contributors may be used to endorse
//   or promote products derived from this software without specific prior written permission.
//
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////////////////////////////////////////////////////////////////////////////////////////////////////

using System;
using System.Collections.Generic;
using System.Text;
using Brainiac.Design.Nodes;

namespace Brainiac.Design
{
	/// <summary>
	/// This class is used to handle circular references.
	/// </summary>
	public class ProcessedBehaviors
	{
		protected List<ReferencedBehaviorNode> _processedBehaviors= new List<ReferencedBehaviorNode>();

		/// <summary>
		/// Used to create a new list of processed behaviours.
		/// </summary>
		public ProcessedBehaviors()
		{
		}

		/// <summary>
		/// Used to branch a new list for its children.
		/// </summary>
		/// <param name="previous">The list of processed behaviours the parent used.</param>
		protected ProcessedBehaviors(ProcessedBehaviors previous)
		{
			_processedBehaviors.AddRange(previous._processedBehaviors);
		}

		/// <summary>
		/// Checks if a node may be processed without running into circular references. The node is not added to the list.
		/// </summary>
		/// <param name="node">The node we want to process.</param>
		/// <returns>Returns true when the node may be processed, if not the calling function has to stop.</returns>
		public bool MayProcessCheckOnly(Node node)
		{
			ReferencedBehaviorNode refnode= node as ReferencedBehaviorNode;
			if(refnode !=null)
				return !_processedBehaviors.Contains(refnode);

			return true;
		}

		/// <summary>
		/// Checks if a node may be processed without running into circular references and adds it to the list.
		/// </summary>
		/// <param name="node">The node we want to process.</param>
		/// <returns>Returns true when the node may be processed, if not the calling function has to stop.</returns>
		public bool MayProcess(Node node)
		{
			ReferencedBehaviorNode refnode= node as ReferencedBehaviorNode;
			if(refnode !=null)
			{
				if(_processedBehaviors.Contains(refnode))
					return false;

				_processedBehaviors.Add(refnode);
			}

			return true;
		}

		/// <summary>
		/// Branches the list for a node.
		/// </summary>
		/// <param name="node">The node we are branching for.</param>
		/// <returns>A new list which contains the previously processed behaviours for referenced behaviours. For other nodes it returns the same list.</returns>
		public ProcessedBehaviors Branch(Node node)
		{
			ReferencedBehaviorNode refnode= node as ReferencedBehaviorNode;
			if(refnode !=null)
				return new ProcessedBehaviors(this);

			return this;
		}
	}
}
